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Constellation X-ray Mission

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1,500 sq cm at 40 keV. Energy resolution 1 keV. 30-60 arc sec HPD angular resolution ... evolution of black hole properties by determining spin and mass ... – PowerPoint PPT presentation

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Title: Constellation X-ray Mission


1
Constellation X-ray Mission
http//constellation.gsfc.nasa.gov
2
Constellation-X Mission Overview
  • Use X-ray spectroscopy to observe
  • Black holes strong gravity evolution
  • Dark Matter throughout the Universe
  • Production and recycling of the elements
  • Mission parameters
  • Telescope area 3 m2 at 1 keV
  • 25-100 times XMM/Chandra for high resolution
    spectroscopy
  • Spectral resolving power 300-3,000
  • 5 times better than Astro-E2 at 6 keV
  • Band pass 0.25 to 40 keV
  • 100 times RXTE sensitivity at 40 keV

Enable high resolution spectroscopy of faint
X-ray source populations
3
X-ray Spectroscopy Comes of Age
Chandra Log N - Log S
The current threshold for finding X-ray selected
AGN exceeds the spectroscopic capability of
optical telescopes to identify the host galaxy
(33 objects at I gt 24) High resolution (Rgt300)
spectrometers on Chandra, XMM-Newton and Astro-E2
typically reach fluxes where the sky density is
0.1 to 1 sources per sq degree
X-ray imaging has outstripped both optical and
X-ray spectroscopy! Constellation-X will
increase by a factor 1000 the number of sources
available for high resolution spectroscopy
Constellation-X will obtain high resolution
spectra of the faint X-ray sources to determine
redshift and source conditions
4
Constellation-X Mission Performance
Two coaligned telescope systems cover the 0.25 to
40 keV band
  • SXT Spectroscopy X-ray Telescope
  • 0.25 to 10 keV
  • Effective area
  • 15,000 sq cm at 1 keV
  • 6,000 sq cm at 6 keV
  • Resolution 300-3000 with combination of
  • 2eV microcalorimeter array
  • reflection grating/CCD
  • 5-15 arc sec HPD angular resolution
  • 5 arc sec pixels, 2.5 arc min FOV
  • HXT Hard X-ray Telescope
  • 10 to 60 keV
  • 1,500 sq cm at 40 keV
  • Energy resolution lt 1 keV
  • 30-60 arc sec HPD angular resolution

5
Plasma Diagnostics with Constellation-X
The Constellation-X energy band contains the
K-line transitions of 25 elements allowing
simultaneous direct abundance determinations
using line-to-continuum ratios
The spectral resolution of Constellation-X is
tuned to study the He-like density sensitive
transitions of Carbon through Zinc
6
Black Holes and Strong Gravity
  • Constellation-X will probe close to the event
    horizon with 100 times better sensitivity than
    before
  • Observe iron profile from close to the event
    horizon where strong gravity effects of General
    Relativity are seen
  • Investigate evolution of black hole properties by
    determining spin and mass over a wide range of
    luminosity and redshift

Simulated images of the region close to the
event horizon illustrate the wavefront of a flare
erupting above material spiralling into the black
hole. The two spectra (1000 seconds apart) show
substantial distortions due to GR effects.
7
Black Hole Evolution
Chandra deep field has revealed what may be some
of the most distant objects ever observed
Chandra
Sources making up the X-ray background
The earliest galaxies
The first black holes
Constellation-X will obtain high resolution
spectra of these faintest X-ray sources to
determine redshift and source conditions
8
Hidden Black Holes
Many black holes may be hidden behind an inner
torus or thick disk of material
Only visible above 10 keV where current missions
have poor sensitivity
9
Cosmology with Clusters of Galaxies
Precision spectroscopy by Constellation-X of
faintest, most distant clusters will determine
redshift and cluster mass and the evolution of
their parameters with redshift
10
The Missing Hydrogen Mystery
  • An inventory of the visible matter in todays
    Universe gives only 20 of the baryons (mostly
    Hydrogen) found at high redshift in the
    Lyman-alpha forest
  • Models for the formation of structure under the
    gravitational pull of dark matter predict the
    "unseen baryons are in a 0.1 to 1 million degree
    K intergalactic gas

HST revealed 15 of these predicted baryons
using UV OVI absorption lines seen against
bright background Quasars - most sensitive to
0.1 million degree gas
Constellation-X will search for the remainder and
can detect up to 70 using O VII and O VIII
absorption lines - most sensitive to 1 million
degree gas
Together, UV and X-ray observations constrain the
problem
11
Galactic Halos
The composition and state of the tenuous hot
halos of Galaxies can be accurately measured via
K or L shell absorption of X-rays against
background quasars
There are more than 300 bright X-ray galaxies for
which such measurements can be made
Spectra of two typical quasars absorbed through
two different hydrogen column densities in the ISM
12
Constellation-X Mission Concept
  • A multiple satellite approach
  • A constellation of multiple identical satellites
  • Each satellite carries a portion of the total
    effective area
  • Design reduces risk from any unexpected failure
  • Deep space (L2) orbit allows
  • High observing efficiency
  • Simultaneous viewing

L2
L2
  • Reference configuration
  • Four satellites, launched two at a time on Atlas
    V class vehicle
  • Fixed optical bench provides a focal length of 10
    m
  • Modular design allows
  • Parallel development and integration of telescope
    module and spacecraft bus
  • Low cost standard bus architecture and components

13
Reference Design
Spacecraft Bus
Spacecraft Bus
Telescope Module
High Gain Antenna
1.6 m Diameter Spectroscopy X-ray Telescope
Mirror and Gratings
Solar Panel
Sunshade
Hard X-ray Telescope Mirrors (3)
Optical Bench (enclosure removed for clarity)
Hard X-ray Telescope Detectors (3)
CCD Array
Cooler with X-ray Calorimeter
14
SXT Design
15
SXT Segmented X-ray Mirrors
  • Requirement Highly nested reflectors with 1.6 m
    outer diameter, low mass and overall angular
    resolution of 5-15 arc sec (HPD)
  • Segmented technology meets mass requirement
  • Requires 10 times improvement in resolution and 4
    times increase in diameter compared to Astro-E2
  • Now the mission baseline - shell mandrels larger
    than 0.7m are not available, plus good progress
    made with demonstrating feasibility of segmented
    approach
  • Recent Progress
  • Demonstrated required performance at component
    level, necessary to begin system level testing
  • Successfully replicated glass segments from 0.5 m
    precision Wolter Mandrel with performance limited
    by forming mandrel
  • Initiated Engineering Unit design
  • Initiated procurement for 1.6 m diameter segment
    mandrel
  • Partners GSFC, MIT, SAO, MSFC

16
SXT Engineering Unit
  • Goal is to approach Con-X resolution requirement
    in unit incorporating all aspects of SXT flight
    system
  • Precisely formed segments
  • Etched Si alignment bars
  • Flight assembly and metrology approach
  • EU is flight-like size (inner module)
  • Utilizes existing Zeiss metal mandrels
  • (50 cm dia. 8.4 m f.l. 5 surface)
  • Phased build up, with increasing complexity
  • Units will be tested in X-rays and subjected to
    environmental testing
  • Delivery mid-2003

Strong-Backs
Combs
Reflectors
Precision Actuators
17
X-ray Calorimeters
  • Requirement 2 eV FWHM energy resolution from 1
    to 6 keV at 1000 counts/s/pixel in 32 x 32 pixel
    array
  • Parallel Approach Transition Edge Sensor (TES)
    and NTD/Ge Calorimeters
  • Progress
  • Demonstrated 2 eV resolution at 1.5 keV and 4 eV
    at 6 keV using TES approach on demonstration
    devices
  • Achieved adequate thermal isolation and 2.5 eV
    resolution at 1.5 keV using a flight sized TES
    device
  • Quantified TES detector noise to enable energy
    resolution budget
  • Fabricated 2 ? 2 TES array for initial cross talk
    measurements
  • Demonstrated a new imaging TES approach that will
    potentially enable increase in field of view
  • Achieved 4.8 eV resolution over full range (1-6
    keV) with NTD/GE detector
  • Partners GSFC, NIST, SAO, UW, LLNL, Stanford

3 mm
2.5 eV (FWHM) _at_1.5 keV
18
Constellation-X Hard X-ray Telescope
  • Requirement Maximum energy gt 40 keV, effective
    area gt 1500 cm2, angular resolution lt 1 arc min
    HPD, FOV 8 arc min, energy resolution lt 10
  • Approach Depth-graded multilayer grazing
    incidence optics (shell or segmented) and CdZnTe
    pixel detectors
  • Progress
  • Successful balloon flights (HERO and Infocus) in
    2001 demonstrated first focused hard X-ray images
  • Improved CdZnTe detector performance
  • Energy resolution 390 eV (at 18 keV) and 550 eV
    (at 60 keV)
  • Threshold (theoretical) is 2 keV 8 keV
    demonstrated
  • Demonstrated sputter coating on interior of
    cylindrical shells
  • Evaluated formed glass prototype optic with 5
    coated surfaces
  • lt 60 arc sec HPD and good reflectance at 60 keV
    (single bounce)
  • Partners Caltech, GSFC, Columbia U., MSFC,
  • Harvard, SAO, NU, NRL

19
Reflection Grating Spectrometer
In-plane Mount
20
Radial Groove Gratings
21
Potential for Greatly Improved Performance
Primary Response
lt35 Response
Extended CCD
ASSUMPTIONS 5500g/mm 15 SXT 2 gratings 2
alignment
Calorimeter 2eV
Mission Goal
I-P n1
Mission Requirement
I-P n2
22
Figure of Merit
20
15
off-plane
calorimeter
area x resolution 106
10
5
in-plane
0
0.1
1.0
10.0
Energy (keV)
23
Top Level Schedule (In-guide FY07 New Start)
24
Summary
  • Constellation-X emphasizes high throughput, high
    spectral resolution observations the next major
    objective in X-ray astronomy
  • A High Priority Facility in the influential
    McKee-Taylor Decadal Survey
  • Mission design is robust and low risk
  • Assembly line production and multi-satellite
    concept reduces risk
  • First launch in 2010 timeframe
  • Facilitates ongoing science-driven,
    technology-enabled extensions
  • Substantial technical progress achieved
  • Replicated segmented reflector performance at
    component level
  • Calorimeter single pixel spectral resolution
  • Hard X-ray telescope optics and detector
    performance
  • Ramping up flight scale technology development
    program
  • On track to demonstrate critical milestones by
    FY04
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